Trimble Lassen LP GPS Receiver

Most GPS receivers implement the ITAR speed & altitude limits simply by not providing any data above, or even before, the 60,000 ft (18km) altitude limit so choices are limited and it's hard to know which receivers are ok for high altitude balloon use unless they are listed on the
W0RPK page. We started with a Trimble Lassen LP GPS and our first BEAR flight was to confirm that it would continue providing data above the ITAR altitude limit. It was an excellent receiver requiring much less power then most, if not all, of the other receivers
being used for balloon flights at the time, but was unfortunately lost on SABLE-2.

Top View of the Trimble Lassen LP GPS

A 3.3 volt regulator board is hot glued to the top of the large I.C.

The tiny 8 pin connector was removed and connections were soldered directly to the circuit to eliminate any possible connector problems.

Bottom View

4 brass standoffs were soldered into the PCB mounting holes to make the GPS easy to mount using four #2-56 screws without worrying how to keep 4 spacers in place while the screws were installed.

The RG-174 antenna feed line was shortened to 12 in. and saved 44.4 grams.

This made the antenna weight 45 grams - almost half.

This receiver can also be seen on the BEAR-1 and BEAR-2 tracker pages.